fix bugs in Deflater and DeflaterOutputStream

Previously, Deflater.deflate would pass Z_SYNC_FLUSH to zlib
unconditionally, which caused the output to be enormous when setInput
was called repeatedly with very small input buffers.  In order to
allow zlib to buffer output and thereby maximize compression, we must
use Z_NO_FLUSH until Deflater.finish is called, at which point we
switch to Z_FINISH.  We also modify DeflaterOutputStream.close to call
Deflater.finish and write any remaining output to the wrapped stream.

classpath/java-util-zip.cpp

@@ -121,7 +121,7 @@ Java_java_util_zip_Deflater_deflate
 (JNIEnv* e, jclass, jlong peer, 
  jbyteArray input, jint inputOffset, jint inputLength,
  jbyteArray output, jint outputOffset, jint outputLength,
- jintArray results)
+ jboolean finish, jintArray results)
 {
   z_stream* s = reinterpret_cast<z_stream*>(peer);
 
@@ -145,7 +145,7 @@ Java_java_util_zip_Deflater_deflate
   s->next_out = reinterpret_cast<Bytef*>(out);
   s->avail_out = outputLength;
 
-  int r = deflate(s, Z_SYNC_FLUSH);
+  int r = deflate(s, finish ? Z_FINISH : Z_NO_FLUSH);
   jint resultArray[3]
     = { r, inputLength - s->avail_in, outputLength - s->avail_out };
 

classpath/java/util/zip/Deflater.java

@@ -27,14 +27,19 @@ public class Deflater {
   private boolean needDictionary;
   private boolean finished;
   private final boolean nowrap;
+  private boolean finish;
 
-  public Deflater(boolean nowrap) {
+  public Deflater(int level, boolean nowrap) {
     this.nowrap = nowrap;
-    peer = make(nowrap, DEFAULT_LEVEL);
+    peer = make(nowrap, level);
+  }
+
+  public Deflater(int level) {
+    this(level, false);
   }
 
   public Deflater() {
-    this(false);
+    this(DEFAULT_LEVEL);
   }
 
   private void check() {
@@ -85,16 +90,15 @@ public class Deflater {
     peer = make(nowrap, DEFAULT_LEVEL);
     input = null;
     offset = length = 0;
+    finish = false;
     needDictionary = finished = false;
   }
 
-  public int deflate(byte[] output) throws DataFormatException {
+  public int deflate(byte[] output) {
     return deflate(output, 0, output.length);
   }
 
-  public int deflate(byte[] output, int offset, int length)
-    throws DataFormatException
-  {
+  public int deflate(byte[] output, int offset, int length) {
     final int zlibResult = 0;
     final int inputCount = 1;
     final int outputCount = 2;
@@ -110,10 +114,10 @@ public class Deflater {
     int[] results = new int[3];
     deflate(peer, 
             input, this.offset, this.length,
-            output, offset, length, results);
+            output, offset, length, finish, results);
 
     if (results[zlibResult] < 0) {
-      throw new DataFormatException();
+      throw new AssertionError();
     }
 
     switch (results[zlibResult]) {
@@ -132,10 +136,15 @@ public class Deflater {
     return results[outputCount];
   }
 
+  public void finish() {
+    finish = true;
+  }
+
   private static native void deflate
     (long peer,
      byte[] input, int inputOffset, int inputLength,
      byte[] output, int outputOffset, int outputLength,
+     boolean finish,
      int[] results);
 
   public void dispose() {

classpath/java/util/zip/DeflaterOutputStream.java

@@ -52,23 +52,25 @@ public class DeflaterOutputStream extends OutputStream {
     } else if (length == 0) {
       return;
     }
-    
-    for (int i = 0; i < length; i+= buffer.length) {
-      deflater.setInput(b, offset + i, Math.min(buffer.length, length - i));
-      while (deflater.getRemaining() > 0) {
-        try {
-          int len = deflater.deflate(buffer, 0, buffer.length);
-          if (len > 0) {
-            out.write(buffer, 0, len);
-          }
-        } catch (DataFormatException e) {
-          e.printStackTrace();
-        }
-      }
+
+    deflater.setInput(b, offset, length);
+    while (deflater.getRemaining() > 0) {
+      deflate();
+    }
+  }
+
+  private void deflate() throws IOException {
+    int len = deflater.deflate(buffer, 0, buffer.length);
+    if (len > 0) {
+      out.write(buffer, 0, len);
     }
   }
 
   public void close() throws IOException {
+    deflater.finish();
+    while (! deflater.finished()) {
+      deflate();
+    }
     out.close();
     deflater.dispose();
   }